Showman Reverb done. Biggest problems were: 1.) a hinky PT (very low voltages --- below 5VAC end-to-end). 2.) New rectifier diodes in the main PS (Fairhchild UF5408 works very nice for these amps. Redone bias power supply.
3.) Replaced the grid-to-ground 68k-ohm resistors on the 6L6GCs, the 47k-ohm resistors on the PI plates. Most couplling caps --- several of those generic OEM brown drop passed more than a 1-2 VDC. And the components under the doghosue.
4.) Sockets showed sign of heat damage. Brittle, with pieces falling off. UNfortunately, this later era SF had 1-inch socket holes & it's hard to find good NOS 1-inch sockets. So had to use Russian made ceramic ones.
5.) R&R the heater lines. And new 100-ohm resistors on the heater-to-ground pseudo-CT. OEM ones read 225 and 310 ohms.
5.) Oh, I put in 2-amp Slow-Blow fuse (amp rec 2.5 amps).
Plate voltage is 468 VDC at the anode. And the idle bias reads -50.2 VDC at the those 68K-ohm resistors. Idle bias current trhough EH 6L6GC = 40-43mA per tube at 468 VDC.
Equals around 19.5-19.8 watts idle dissipation per tube.
Tone is very clean. Loud (though a four by 10-inch cab). A little "tight." Prolly due to components still breaking-in.
See how this amp behaves, over time. http://www.webphix.com/schematic%20heav ... _schem.pdf